Area that was biggest waste?

Fantasy Theme Park, and maybe even Ariant, seems to be neglected.

Ariant was quite interesting when it was introduced. I liked the quest line, it had a good story and it had puzzles, not just "kill these and collect those because I want you to".
With the latest "revamp" and "streamlining" (read: dumbing down) the quest line was gutted, and the new level of the mobs is not too useful for training, so the area is neglected.

I suppose if by "big waste" we include areas that were good or had potential but were destroyed or allowed to rot, then that counts. But I understand it to mean areas that were useless as soon as they appeared, a complete waste of development effort, like Twisted Aqua Road. Fantasy Theme Park qualifies.